符合线路显像与^(18)F最佳活度的关系  

Relationship of the sensitivity of dual-head coincidence imaging and ~18F activity

作　　者：史德刚[1] 苗积生[2] 黄钢[3] 

机构地区：[1]广州中医药大学附属佛山中医院放射科,佛山528000 [2]上海市肺科医院核医学科 [3]上海第二医科大学附属仁济医院核医学科

出　　处：《中华核医学杂志》2005年第6期377-378,共2页Chinese Journal of Nuclear Medicine

基　　金：上海市卫生局科技发展基金资助项目(99439).

摘　　要：目的探讨符合线路显像^(18)F给药活度对随机符合比率及显像灵敏度的影响。方法胸部模型充满不同^(18)F活度的水溶液,用 DST-Xli 双探头 SPECT 仪符合采集发射影像,并进行图像处理。结果真符合减去随机符合,相应的^(18)F活度之差越大显像效果越好,6次显像该差值由小变大再由大变小,在86 min 时差值最大为8.9 MBq.单光子计数率3.65×10~5,^(18)F 相应活度17.8 MBq,随机符合比率25%,出现阳性结节最多,显像效果最好。6次显像的单光子计数率、随机符合比率等彼此间均存在直线相关性。活度(X,MBq)与随机符合比率(Y,%)的相关系数平方(R^2)为0.9974,校正的 R^2为0.9967,P<0.0001,直线方程 Y=-1.893 79+1.550 685 X。结论模型显像可测出符合线路显像的最佳^(18)F 给药活度;当随机符合比率为25%时对应的^(18)F活度为最佳活度,可取得最灵敏的显像效果。Objective To evaluate the effects of ^18F activity on random coincidence rate and sensitivity in dual-head coincidence imaging. Methods The chest model was filled with water solution added various ^18F activity, The emission tomography imaging was acquired by DST-XIi dual-head SPECT and the imagings were processed with the same reconstruction procedure, Results The more different between the true and random coincidence, the belier imaging quality would be. The difference value varied from small to large and then gradually went down in 6 consecutive imagings, At 86th nlin, the difference value reached maximum 8.9 MBq, the single counts rate was 3. 65 × 10^5 , the corresponding ^18F activity was 17.8 MBq, and the random coincidence rate was 25% . At thal time the most positive nodules were displayed with the best imaging quality. The cnunts rate, random coincidence rate and others had significant linear correlation. The correlation coefficient （R） between the activity X （MBq） and random coincidence rate Y （%） were 0. 9974 （ R^2 ） and 0.9967 （ R^2 ） with P 〈 0, 0001, and the linear equation was Y = - 1. 893 79 ＋ 1.550 685 X. Conclusions Chest model suggested the best suitable ^18F activity required; both higher or lower activity could not benefit for the imaging quality. When the random coincidence rate was 25% , the corresponding ^18F activity could produce the best imaging sensitivity.

关 键 词：氟放射性同位素 体层摄影术 发射型计算机 单光子 放射性 质量控制 

分 类 号：R817[医药卫生—影像医学与核医学]